Send mavlink message for drone go to specific position

MAVLink
1

hello guys i’m using mavlink c++ applications. after the drone takeoff, i would like to send the mavlink message to tell the drone to go to a specific location.

  • My firmware PX4 autopilot
  • Mavlink 2 c++

i was archived that by change drone to OFFBOARD mode and then send the position_target_global_int message.

but my target is do the similar thing like the QGroundcontrol do without change the drone mode. the goto_position when click to the QGC screen.

i also used mavlink MAV_CMD_DO_REPOSITION message

mavlink_msg_command_long_pack(
        system_id,              // System ID of GCS
        component_id,           // Component ID of GCS
        &message,               // MAVLink message
        target_system,          // Target system ID
        target_component,       // Target component ID
        MAV_CMD_DO_REPOSITION,                // Command ID
        current,                // Confirmation (0: first transmission)
        param1,                 // Parameter 1
        static_cast<float>(MAV_DO_REPOSITION_FLAGS_CHANGE_MODE),                 // Parameter 2
        param3,                 // Parameter 3
        param4,                 // Parameter 4
        int32_t(std::round(latitude * 1e7)),               // Parameter 5: Latitude
        int32_t(std::round(longitude * 1e7)),              // Parameter 6: Longitude
        60                // Parameter 7: Altitude
    );

but the drone keep moving south and not go to my target
please help me !

2

it might be easier to use MAVSDK instead of low level mavlink2.
then, you can use this example for creating a mission:
https://mavsdk.mavlink.io/v1.4/en/cpp/examples/fly_mission.html

you might also want to read more about differences between offboard and mission modes:
https://mavsdk.mavlink.io/v1.4/en/cpp/guide/missions.html
https://mavsdk.mavlink.io/v1.4/en/cpp/guide/offboard.html

In short, as I understand when you click in QGC for “go to”, it creates a mission. and yes, you can create this missions programmatically with mavlink.

3

Hi, thank you for the reply. however, i dont think click goto_position in QGC will create a mission. a very small example is i uploaded a plan in to drone. start mission then pause (the drone will be HOLD mode). click goto_position. the drone keep in (HOLD mode) but it move to desired position and the old plan still in the drone firmware

4

yes, you are right for that feature it must be
MAV_CMD_OVERRIDE_GOTO

Still it would be much easier to use it with MAVSDK Action API “goto_location” (should be a wrapper around the same command):
https://mavsdk.mavlink.io/main/en/cpp/api_reference/classmavsdk_1_1_action.html#classmavsdk_1_1_action_1afb3546fa994357e491816f2032716818